Improvement in telephone exchange systems and devices



2. Sheets-Sheet 1.

F.. SHAW. Telephone-Exchange System and Devices.

No. 220,874. Patented Oct. 21,1879.

mafia? 21% MM N. PEIERS, PHOTO-LITHOGRAPHER, WASHINGTON. D c.

2 Sheets-fiheet 2.

, F. SHAW. Telephone-Exchange System and Devices.

N-o.,220,874. Paten ted Oct. 21, 1879.

STATmN NBA- ggwmm 3 Y NPEIERSI PNOTO-LITHOGRAPHER. WASHXNGTDN, D C.

UNITED. STATES PATENT OEEIoE.

FRANK SHAW, OF NEW YORK, N. Y., ASSIGNOR TO LAW TELEGRAPH COMPANY, OF SAME PLACE.

IMPROVEMENT IN TELEPHONE EXCHANGE SYSTEMS AND DEVICES.

Specification forming part of Letters Patent No. 220,874, dated October 21, 1879 application filed August 11, 1879,

To all whom it may concern:

Be it known that I, FRANK SHAW, residing at No. 9257 Third avenue, in the city, county, and State of New York, have invented a new and useful Improvement in Telephonic Exchange Systems and Devices, of which the following is a specification.

The object of myinvention is to enable any one of a large number of subscribers to what is commonly known as a telephone intercommunication exchange, district,.or central office system to be quickly, easily, and without confusion put in private and-direct communication at any time with any other subscriber.

The plan upon which such' exchanges are usually constructed and operated consists in extending a single wire from the central office or exchange to the offiees or houses of one or more subscribers, completing the electrical circuit by ground or other usual connections and by suitable call, receiving, and transmitting apparatus-i. a, telephones, signals, &c.--locat'ed at the central office and at the offices or houses of each subscriber, and in centerin g as many suchsingle wires as the numberof subscribers requires, so that at any time any subscriber can callthe attention of the central office through this single wire, and then by each switching the wire to a telephone can make known to the central office the. subscribers name with whom he wishes to 'communicate, and the central office can the'n call the attention of such subscriber by meahs of hlssingle wire, and place the two in direct communication by the same wires over which theivari'ous signals have passed. In order to ascertain when they havefinished their communication, thecentral office either retains its telephone in circuit and listens, or maylisten to or overhear the conversation, or it places an annunciator in circuit, which can be dropped byeither subscriber when theconversation is finished.

' This systemis open 1110 several serious ob ject-ions, as follows: First, it frequently leads to confusion, because many subscribers sometimes do, and all may, at one time call or signal to the central office for connections, which cannot be properly. received and executed simultaneously; second, it requires a large num= ber of operators for such emergencies, who at other times stand about idle and unemployed; third, it consequently leads to frequent mistakes and delays; fourth, it requires considerable space and a large amount of apparatus.

Therefore, while this system seems simple, owing to the use of a single wire for calling the central office and communicating with a subscriber, and the same wires for communicating between subscribers, it is in fact complicated in operation.

I overcome these objections by employing two wires and circuits-one for connection or, disconnection calls or signals, and the other for private communication between subscribers constructed and operated in the manner hereinafter set forth.

It has been found that where there is a considerable number of subscribers, where firmnames are composed of several individual names, and especially where more than one subscriber has the same name, confusion and mistakes are likely to occur both at the central office and at subscribers stations. I avoid these difficulties by numbering each station and printing a schedule or list of subscribers, with the name or title of the subscriber opposite the number of his station, which list or schedule is posted up near the instruments at eachstation and office. The calls and notices for connection are then all conducted without error by the use of numbers to designate the subscriber, which fixes absolutely the actualparties desiring to comm unicate or communicating.

My invention consists in the several combinations, methods of operation, and systems set forth in the several claims annexed hereto.

From each subscribers station I run two wires to a common central office, one of which wires I preferably run to no other station or stations, although several stations may be 10- cated thereon; and the other wire I run to as many other subscribers stations as the amount of-business done by them warrants. The first is the private and the last is the call or signal wire. These wires are provided with a battery or other source of electricity, and with a suitable switch-board and instruments at the common central office, and suitable instru ments and batteries or other source of electricity at all the stations. Then any one subscriber can at any time obtain private and direct telephonic communication with any other subscriber by requesting the common central oflice, by means of the last-mentioned call or signal wire, to connect together the private wires of the two subscriber-stations, and atterward,havin g finished theircommunications, can signal in like manner the common central station to disconnect said private lines, so that either may be in readiness to be connected at any moment with the private line of any other station.

The call or signal wire being common to a considerable number of subscribers stations, and the instruments there, the result is, that a subscriber, on going to his instruments, is able to learn whether or not any other subscriber is signaling, and to wait his turn, or until the call or signal wire is not in use before attempting to signal. The result is, that the subscribers, as it were, form themselves in cue, each taking his place in succession. At the ofiice end of the signal-wire I place a receiving operator, who sits with the receiving-instrument or telephone constantly at or near his ear, ready to receive the name or number of any subscriber desiring to communicate, and of the correspondent with whom he desires to be placed in communication. The names or numbers so received he repeats, so asto be heard by the subscriber callingthrough the transmitting-instrument in front of him, and at the same time, by another operator at the switch-board in the central oftice, who instantly connects the two private wires and subscribers so indicated. As he does so the operator at the switch board notifies both subscribers by means of a bell in circuit on the wire. The same course is pursued when the conversation is concluded and disconnection is desired, except as to the ringing of the ell.

Figure 1 is a plan of my system for connecting a central ofiice and its subscribers. Fig. 2 is a plan of my system for connecting the subscribers who belong to one central oflzice with those who belong to another central oflice. Fig. 3 is a plan, showing two subscribers stations and central office with instruments and receiving operator in position.

In Fig. 1, X represents a central office or station, and a b 0 represent a given number of subscribers stations, each of which is connected with the common central office or station by two wires, the first of which is marked W, and the second a b 0, respectively, and also W in common.

Now, if the subscriber at station a wishes to communicate with the subscriber at station b, he makes known the fact to the listening operator at the central station, X, by means of the wire W, and immediately the listening operator notifies the operator at the switch-board in the central oifice, X, who connects together the wires or and b (which are all private wires,

indicated as such by the letter W) by any usual switch and switch-board, and also notifies the subscriber calling for the connection, by means of the transmitter near him, provided the subscriber desires and retains his receiving-instrument in connection with the transmitter or on the same wire. As previously stated, the switchboard operator notifies each subscriber ot' the connection by ringing a bell in the cities of each by means of a battery.

The subscribers at stations a and b having finished their communications, which they conduct entirely in private without being overheard by any one in the central .oflice or elsewhere, either one makes known the fact to the operator in the central ofiice at X by means of the wire \V, who immediately disconnects the wires a and D which are then in readiness to be connected at any time with the similar wire of any other subscribers station.

In cases where distances are great, I estab' lish two or more common central stations, converging at each the wires from all stations nearest to it, and connecting all the common central stations together by as many wires as may be required.

Now, should a wish to communicate with the subscriber of any other central oflice, as d, Fig. 2, he makes known the fact to the operator at X by means of the wire W, who immediately connects the wire a? with one of the wires A, A, or A, and instructs the operator at the station Z, by means of another of the wires A, A, or A", used as a call or signal wire between central stations, (two or more,) to connect the wire at withthe wire, A, A, or A", first mentioned.

The disconnection is accomplished either by the subscriber at station a notifying the operator at the central station,'X, and he notifying the operator at the other central station, Z, by the same wires as before, or by the subscriber at the station d notifying the operator at Z, and he notifying the operator at X.

In Fig. 3, stations Nos. 1 and 2 represent the instruments in two subscribers stations, wherein R It are the receiving-instruments, and (J C are the transmitting-instruments, with the usual wire connections, coils, and batteries.

S S are switch devices for connecting the instruments at will with either the call or signal wires or with the private wires. S is the central-ofiice connecting-switch board, whereby the private wires are connected at the central stations by inserting theends E E into.

holes H H in the bar or. strip B. 0 represents the receiving-operator, with the receiving-instrument at his ear, and the plate P of a transmitting-instrument in front of him, by means of which he answers orrepeats hackto any subscriber on the call wire. W is the call or signal wire, and W the rivate wire. S" represents the helix and. signal hell, with ground-wire G.

The connecting or switch-board operator,

before inserting the ends E E in the bar-B by touching them upon thebarB, connected with the battery or series of cells C and its ground- Wire G, rings the bells D by means of the circuit through the wire W, its studs or connections F F, helix S and lever L.

The spring S' on the end of the stemof the switch S forces back the switch, so that the central oflfice may always call the subscriber, since his signal-bell is always thereby left in circuit. On calling or being so called thesubscriber takes his receivinginstrument from its holder H, which allows the holder to rise and make the connection at K, which brings the transmitting apparatus and its battery into circuit.

P is the plate of the transmitter, which is a Blake transmittingtelephone or other like transmitter. The subscriber places the receivin g-instrument to his ear, is ready to'hear from the central office,.and to talk either with the central office, or, when the private-wire connection is made, with the co-subscriber. If, now, the subscriber desires to communicate with the centralzofficealone by the call or signal wire, he pushes in the switch S, which connects his transmitter with the call-wire 'W, and permits him to communicatewith the operator in the central oflicezyand on releasing the switch S the spring S throws back the switch and connects his receiving and transmittin g instruments with the private wire W alone.

I claim as my invention- 1. In a telephonicexchange system, the signal-wire W, extending to a series of subscriber direct private to one or more stations, in combination with wires W W, each extending subscriber-stations.

2; The method of operating a telephonic-exchange system, consisting in placing areceiving-operator at the central-oflice end of a signal-wire common to a series of subscriber-stations, to repeat the directions received by telephone to a switch-board operator, who thereupon connects the two private wires of the two subscribers between whom communications are to pass.

3. In a telephonic-exchange system,the signal-wires W W of two or more central offices or stations, and the private wires W W of the same oftices or stations, connected by the intermediate wires, A, A or A arranged and operating in the manner and for the purpose shown and described.

4. In atelephonic-exchange system, the signal-wires'W, the private wires W, the receiving-instruments R, the transmitting-instruments 0, the switch devices S, the central switch-board, S, the connecting ends E, and bar B, all in'combination, as and for the purposes set forth.

5. In a telephonic exchange system, the switch S, in combination with the call-wire W and private wire W, when used and operated in the manner shown and described.

In testimony whereof I have hereunto set my hand this 31st day of July, A. D. 1879.

' FRANK SHAW.

Witnesses:

GEORGE A. HAMMEL, WILLIAM EOKHARD. 

